Prepare the pigeon breasts by cutting them into small pieces.

Finely dice the onion, celery, leek, and carrot.

Heat 1 tablespoon of olive oil in a frying pan over medium heat.

Fry the pigeon, chicken livers, and pancetta in olive oil until lightly browned.

Transfer the browned meat mixture to a pie dish.

Add another tablespoon of olive oil to the frying pan.

Fry the onion, celery, leek, and carrot until golden brown.

Add the fried vegetables to the pie dish.

Fry the button mushrooms and shallots in the remaining oil.

Add the fried mushrooms and shallots to the pie dish.

Spoon tomato paste into the pan and cook for 1 minute.

Deglaze the pan with game or chicken stock, scraping up any browned bits.

Add peppercorns, rosemary, sage, and thyme to the stock.

Bring the stock to a boil.

Preheat the oven to 375°F (190°C).

Pour the hot stock over the meat and vegetables in the pie dish.

Roll out the shortcrust pastry to cover the pie dish.

Place the pastry over the pie dish, crimping the edges to seal.

Bake for 45 minutes, or until the pastry is golden brown and the filling is bubbling.

Serve immediately.